1. Field of the Invention
The present invention relates to a mobile apparatus for loading and transporting an assembled track section consisting of rails fastened to ties and for laying the track section on a track bed, which comprises a track section hoisting device comprising an elongated carrier frame extending in the longitudinal direction of the track bed, pairs of lifting jacks spaced from each other in this direction, and drive means for vertically adjusting the lifting jacks between a retracted position and an extended position in which the lifting jacks support the carrier frame on the track bed. The apparatus also comprises an elongated self-propelled transport car for supporting an assembled track section and the hoisting device, the transport car being movable in this direction independently of the hoisting device and having two opposite ends spaced from each other in said direction, and track-bound undercarriages and vertically adjustable off-track undercarriages adjacent each end of the transport car.
2. Description of the Prior Art
Such a mobile apparatus is known from U.S. Pat. No. 4,784,063 and comprises a transport car and a hoisting device which is independent of the transport car and may be driven to and from an operating site with an assembled track section loaded on the car. When an assembled track section consisting of rails fastened to ties, such as a track switch, is to be removed and replaced, the transport car is moved in the longitudinal direction of the track bed to dispose the hoisting device comprising an elongated carrier frame extending in this direction above the assembled track section, whereupon the carrier frame is supported on the track bed by lowering the lifting jacks into engagement with the track bed while the lifting jacks lift the carrier frame off the transport car. The transport car is then moved off the operating site, the carrier frame is lowered by the lifting jacks toward the track section to be removed, the track section is gripped with vertically adjustable clamping devices on the carrier frame, and the lifting jacks are again operated to raise the carrier frame carrying the track section. The off-track undercarriages on the transport car are then lowered and the transport car is moved back to the operating site on the off-track undercarriages underneath the raised carrier frame and track section. The track section may then be lowered onto the transport car to be transported away from the operating site. This sequence of operations is reversed to place a new track section on the track bed after an old track section has been removed. If the track section is very long, two such mobile installations arranged one behind the other are used.
A similar apparatus has been disclosed in U.S. Pat. No. 4,773,332. In this installation, the hoisting device has two track-bound undercarriages and a pair of lifting jacks at each undercarriage so that the hoisting device may be moved along the track as well as the track section to be removed or to be inserted in the track. The hoisting device and the assembled track section may be loaded on the transport car.
German patent No. 3,419,205 discloses a track maintenance machine for laying and removing a track section, which is comprised essentially of an elongated carrier frame consisting of two parts connected to each other by a cardan joint. Retractable track-bound and off-track undercarriages are arranged at each end of the carrier frame and at the cardan joint to support the carrier frame selectively on the track or the ballast bed of an operating site from which a track section has been removed. Vertically adjustable gripping devices on the carrier frame clamp the track section to the carrier frame.